tbuckley/cabot-search huggingface dataset:
Abstract P3187: Deletion Of SARM1 NAD Hydrolase Ameliorates Diabetic Cardiomyopathy By Regulating Mitochondrial Metabolism And Mitophagy
Authors: Hina Lateef Nizami, Keaton Minor, Ignacy Gorecki, Christine Light, Ying Ann Chiao, Haiwei Gu, Chi Fung Lee
Journal: Circulation Research (2023)

Diabetes is a major risk factor of heart disease. Decline of NAD, a redox cofactor in cellmetabolism, is a hallmark of cardiometabolic disease. Here, we test if inhibiting NAD consumptionmay be therapeutic in diabetic cardiomyopathy. SARM1 is an intracellular NAD hydrolase thatpromotes neuronal death. However, its role in diabetic hearts has never been reported. Wehypothesized that SARM1 deficiency attenuates diabetic cardiomyopathy and aimed to determineunderlying molecular mechanisms.C57BL/6N wild-type (WT) and SARM1-knockout (KO) male mice were injected with streptozotocin(STZ) induce type 1 diabetes (T1D). 16-week T1D stress caused progressive systolic (fractionalshortening) and diastolic dysfunction (E’/A’, e/E’) in WT mice. T1D-KO mice had attenuatedsystolic and diastolic dysfunction, despite similar elevation of fasting glucose and no significantdifferences in plasma metabolites (243 aqueous and lipid species) from T1D-WT and T1D-KOmice. T1D-WT hearts had reduced NAD pool compared to non-diabetic (ND-WT), which waselevated by SARM1 deletion. T1D-WT hearts had upregulated cardiomyopathy gene markers(Nppb, Myh7/Myh6 ratio) that were normalized in T1D-KO hearts. Chronic T1D induced cardiacfibrosis and upregulation of profibrotic genes (Ctgf, Inhbb), both of which were attenuated in T1D-KO hearts. RNA-seq analysis identified 1948 differentially expressed genes in T1D-WT hearts,compared to non-diabetic WT hearts. Gene Module Network Analysis identified suppressedmitochondrial processes in T1D-WT hearts. Expressions of a majority of genes from complexes Ito V were lowered in T1D-WT hearts and partially reversed in T1D-KO, suggesting that SARM1promotes mitochondrial dysfunction in diabetic hearts.Mitochondria of T1D-WT hearts had 50% reduction in ADP-driven respiration compared to ND-WT, which was reversed in T1D-KO mitochondria. T1D-WT hearts had elevated expression ofBNIP3 and mitochondrial recruitment of LC3B, which were attenuated in T1D-KO hearts. Insummary, our data suggest that SARM1 regulates mitochondrial metabolism and mitophagy indiabetic hearts. However, underlying pathogenic mechanisms of SARM1 in diabetic heart andtranslational potential of SARM1 inhibition require further investigation.
Abstract P3079: Integrating Existing Cardiac Single-cell RNA Sequencing Datasets To Uncover The Role Of B-cells In Heart Disease
Authors: Kevin Bermea, Aashik Bhalodia, Charles D Cohen, jana lovell, Sylvie Rousseau, Marcelle D Zita, Luigi Adamo
Journal: Circulation Research (2023)

Introduction: The role of B-cells in human heart failure remains unclear. To address this knowledge gap, we analyzed publicly available datasets of scRNAseq and snRNAseq from patients with various forms of cardiomyopathy. Methods and Results: We used two public datasets including single cells or single nuclei RNAseq data collected from the myocardium of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), dilated cardiomyopathy (DCM), idiopathic cardiac diseases (ICD), or healthy controls. The first dataset comprised 30 healthy controls and 22 non-ischemic DCM; the second contained 18 controls and 61 with DCM, ARVC, or ICD. Data were normalized and scaled, a UMAP plot was generated, and cells were classified using ScType. B-cells were merged into a single matrix, and the final dataset contained 1100 cells from 32 healthy controls, 59 DCM, and 8 ARVC patients. Four different B-cell clusters were identified. The top 100 biomarkers from each cluster were used to identify B-cell subtypes. Cluster 1 was identified as transitional splenic B-cells; Cluster 2 as plasma cells; Cluster 3 as follicular splenic B-cells; Cluster 4, present only in DCM, as immature B cells. Ingenuity Pathway Analysis (IPA) of the genes enriched in each cluster highlighted that different B cell clusters displayed distinct biological activity, ranging from phagosome formation to B cell receptor signaling and cytokine production. Differentially expressed gene analysis comparing healthy controls to DCM and ARVC showed both similar and disease-specific gene expression patterns in the various B cell clusters. For instance, cluster 2 showed upregulation of oxidative phosphorylation in both DCM and ARVC. On the other hand, DCM cluster 2 showed downregulation of CD40 signaling, while in ARVC the same cluster showed downregulation of IL-6 signaling (Z score &gt;2, p&lt;0.05). Discussion: Our findings suggest that human heart failure is associated with perturbations in B cell gene expression, with both shared and disease-specific features. This data supports the notion that B cells likely play a role in human cardiomyopathy. Further, this data suggests that B-cells play distinct roles in disparate forms of cardiac disease.
Abstract P1142: Environmental Regulation Of LncRNAs In Human Congenital Heart Defects
Authors: John Hwang, Kang Xuedong, Marlin Touma
Journal: Circulation Research (2023)

Introduction: Long non-coding RNA (lncRNA)-mediated transcriptional regulation is emerging as an important regulatory mechanism during development and diseases affecting all aspects of transcriptome programming. However, how systemic hypoxia alters lncRNA regulation in congenital heart defects (CHDs) remains poorly understood. Objectives: To examine the impact of systemic hypoxia on lncRNA-mediated regulatory networks in CHDs. Methods: Deep bulk RNA-seq datasets were derived from specimens of ventricular septum defects (VSD), tetralogy of fallot (TOF), and control hearts. TOF stratification (cyanotic vs noncyanotic) was based on average O2 saturation levels. Correlation statistics served to identify the lncRNA-mRNA pairs. The lncRNA-mRNA networks were generated using weighted gene co-expression network analysis (WGCNA). Results: Principal component analysis showed that lncRNAs from CHDs and control samples formed distinct clusters. Compared to control, 385 lncRNAs were differentially expressed in CHDs (adj P ≤ 0.05) with 15% exceeded two-fold change in TOF. Subgroup analysis of the TOF cohort, revealed 111 differentially expression lncRNAs in cyanotic compared to noncyanotic TOF, after normalization to control. Out of 850 lncRNAs located within 50 kb of a protein coding genes, 65% exhibited significant correlation with the expression of their partner genes at Pearson’s correlation coefficient -0.7≤ and ≥0.7 and B-H corrected P value ≤0.05. The partner genes were enrichment with cardiac development, RNA processing, and chromatin remodeling. WGCNA identified nine lncRNA-mRNA modules specifically associated with clinical diagnosis or hypoxia status. Furthermore, NONHSAT05860 and NONHSAT049671 were identified as the top hypoxia-associated hub lncRNAs, potentially driving the molecular network of cyanotic TOF. Conclusions: The study revealed a high-resolution landscape of lncRNA contribution to transcriptome regulation in CHDs and uncovered hypoxia-associated lncRNA-mRNA regulatory circuits in cyanotic TOF. NONHSAT05860 and NONHSAT049671 were significantly influenced by systemic hypoxia providing conceptional basis for future investigations of their specific roles in transcriptome programming in cyanotic TOF.
Abstract P1153: ANT-Dependent MPTP Contributes To Necrotic Myofiber Death In Muscular Dystrophy
Authors: Michael J Bround, Julian Havens, Allen York, Michelle Sargent, Jeff D Molkentin
Journal: Circulation Research (2023)

The Mitochondrial Permeability Transition Pore (MPTP) is a critical cell death mechanism that contributes to ischemia reperfusion injury in the heart and several degenerative diseases, including Muscular Dystrophy (MD). MD is a family of genetic disorders characterized by progressive muscle wasting, loss of muscle function, and premature death. We have recently demonstrated that the MPTP has two defined genetic components: one consisting of adenosine nucleotide translocase (ANT) family of proteins and a second, unidentified pore that requires the protein cyclophilin D (CypD) to activate. In this study we used MD as a model to test whether this new MPTP model could be applied to a physiological context of necrotic cell death in vivo . We observed that genetic deletion of ANT1 or CypD substantially reduced MD pathology in skeletal muscle, with reduced measures of muscle necrotic cell death, and improved muscle function compared to MD control animals. However, both ANT1KO and CypDKO MD mice still displayed elevated rates of cell death and MD pathology compared to healthy wildtype animals. MD mice lacking both ANT1 and CypD (ANT1KO-CypDKO) virtually eliminated features of skeletal muscle pathology in MD. We observed a near complete loss of MD histopathology, undetectable levels of tissue necrosis, and muscle function that was improved to non-MD levels in ANT1KO-CypDKO MD mice. This study demonstrates that inhibiting both the ANT-dependent and CypD-dependent components of MPTP together can prevent necrotic cell death in an in vivo model. This study also suggests that a therapy that inhibits both MPTP-components can effectively treat MD and may potentially reduce cardiac ischemia reperfusion injury.
Abstract P2064: A Specialized Centrosome-Proteasome Axis Mediates Proteostasis And Influences Cardiac Hypertrophy
Authors: Jared M McLendon, Xiaoming Zhang, Ryan L Boudreau
Journal: Circulation Research (2023)

Mature cardiomyocytes (CMs) lack centrosomes. Instead, centriolar and satellite proteins redistribute into specialized perinuclear organelle-like compartments, where they likely serve multifunctional roles, e.g., in organizing microtubules and establishing localized clearance of aggregated/misfolded proteins via the ubiquitin-proteasome system (UPS). Taxilin-beta (Txlnb) is a CM-enriched protein that localizes perinuclear and belongs to the family of taxilin proteins, which are centrosomal proteins that have been implicated in protein quality control. We hypothesize that Txlnb plays key roles maintaining specialized centrosomal-proteasomal crosstalk in CMs. We first examined proteostatic roles for Txlnb in neonatal rat CMs treated with phenylephrine and found that Txlnb overexpression coordinately increased protein synthesis and proteasome activity, while decreasing ubiquitin-protein conjugate accumulation. We generated Txlnb knockout (Txlnb-KO) mice, which show robust accumulation of ubiquitinated proteins and decreased 26SB5 proteasome activity in heart tissues, as well as lower cardiac mass with aging. To test if Txlnb influences proteotoxic UPS dysfunction, we crossed Txlnb-KO mice to Cryab-R120G transgenic mice, a model of severe cardiac proteotoxicity with progression to heart failure and early death. Loss of Txlnb resulted in worsening of heart failure, evidenced by lower ejection fractions in Txlnb-KO/Cryab-R120G mice versus Cryab-R120G littermates. By contrast, AAV-mediated Txlnb overexpression in Cryab-R120G mice resulted in only slight reduction in myocardial wall thickness but was overall insufficient to slow heart failure progression. To test if Txlnb influences hypertrophic UPS dysfunction, Txlnb-KO and wildtype (WT) mice were subjected to cardiac pressure-overload induced by transverse aortic constriction (TAC). At 6-weeks post-TAC, Txlnb-KO mice showed reduced ejection fraction, increased heart mass, and elevated accumulation of ubiquitinated proteins, relative to WT mice. Together, these data provide initial evidence connecting Txlnb to proteostatic functions in cardiomyocytes, hinting at the potential importance of functional bridging between specialized centrosomes and UPS in CMs.
Abstract P1118: Engineering A Patient-specific Heart On A Chip Model Of Hypoplastic Left Heart Syndrome
Authors: Riya Verma, Megan L Rexius-Hall, Megan L McCain, Ram Kumar Subramanyan
Journal: Circulation Research (2023)

Hypoplastic Left Heart Syndrome (HLHS) is the most expensive congenital cardiac disease and is characterized by underdevelopment of the left side of the heart. The surgical intervention leads to the developmentally disadvantaged right ventricle performing systemic circulation. As such, a subset of HLHS patients develops progressive heart failure that results in limited transplant-free survival. There are no animal models to study the molecular and functional properties of HLHS cardiomyocytes, limiting our understanding of disease mechanisms and human genotype-phenotype relationships. To address this, we are creating a physiologically and functionally relevant ”heart on a chip” model of HLHS hiPSC-derived cardiomyocytes (CMs). Induced Pluripotent Stem Cells (iPSCs) were derived from cord blood mononuclear cells isolated from the umbilical cord blood from 8 antenatally diagnosed HLHS children at birth. Control (iPSCs) from 3 healthy subjects were derived from peripheral blood mononuclear cells. We then differentiated ventricular CMs from these iPSCs using StemDiff ventricular CM kit. We observed HLHS iPSCs formed ~50% fewer CMs compared to healthy controls. We studied calcium handling by iPSC-CMs with Fluo-4 fluorescent calcium dye in HLHS and Healthy iPSC-CMs. We observed that calcium transients in HLHS-CMs have half the beat rate, 1.4 times longer rise time to rise, 1.5 times higher time constant (Tau), compared to Healthy CMs, suggesting that HLHS CMs have dysfunctional calcium handling compared to healthy CMs. Our results demonstrate that in an in vitro model of iPSC-derived CM, HLHS patient CMs demonstrate reduced formation and defective calcium handling, which may potentially explain the pathogenesis of heart failure in HLHS patients. In ongoing experiments, we are evaluating diastolic and systolic stress generation in these cells. We will also establish the underlying molecular mechanisms of functional defects in HLHS CMs and screen potential drug therapies for single-ventricle patients.
Abstract P2117: Hypoadiponectinemia-induced Epigenetic Downregulation Of Endogenous Antioxidants Exacerbates Cardiac Ischemia-reperfusion Injury In Diabetic Mice
Authors: Jianli Zhao, Zhijun Meng, Yalin Wu, caihong liu, Erhe Gao, Walter J Koch, Fujie Zhao, Bernard L Lopez, Theodore Christopher, Jianyi J Zhang, Xinliang L Ma, Yajing Wang
Journal: Circulation Research (2023)

Diabetes worsen myocardial ischemic/reperfusion (MI/R) injury, but the underlying mechanism is still not fully understood. Epigenetics regulation is markedly involved in the process. Adiponectin (APN), a cardioprotective adipokine, is suppressed by diabetes, and dysregulated miRNAs are implicated in disease development. However, it is unclear whether hypoadiponectinemia alters cardiac miRNA profile, contributing to diabetic heart injury. Wild-type (WT) and APN knockout (APN-KO) mice were subjected to MI/R and cardiac microRNA profile were determined. Comparing those miRNAs that increased in APN-KO mice following MI/R, miR-449b was most significantly upregulated (3.98-fold over WT mice). Administering miR-449b mimic increased apoptosis, enlarged infarct size, and impaired cardiac function in WT mice. In contrast, anti-miR-449b decreased apoptosis, reduced infarct size, and improved cardiac function in APN-KO mice. In depth Bioinformatic analysis revealed oxidative stress as the top pathway regulated by miR449b. Venn analysis followed by luciferase assay identified Nrf-1 and Ucp3 as the two most important miR-449b targets. Administrating anti-miR-449b to APN-KO mice attenuated MI/R-stimulated superoxide overproduction. High glucose/high lipid in vitro treatment simulated ischemia/reperfusion upregulated miR-449b, leading to inhibition of Nrf-1 and Ucp3. These pathological effects were attenuated by anti-miR-449b or Nrf-1 overexpression. Clinically relevant cohorh study in high-fat diet (HFD)-induced diabetic mice followed with MI/R identified the copied pheonotype. Administration of anti-miR-449b or APN preserved cardiac Nrf-1 expression, reduced cardiac oxidative stress, decreased apoptosis and infarct size, and improved cardiac function. In conclusion, the study shows that hypoadiponectinemia upregulates miR-449b, suppressing Nrf-1/Ucp3 expression, which leads to oxidative stress and worsens MI/R injury. The APN/miR-449b/oxidative stress pathway could potentially be a therapeutic target for diabetic MI/R injury.
Abstract P2129: Myocardial Stunning Model In Rats
Authors: Ahmed Elmahdy, Aaron Shekka Espinosa, Shafaat Hussain, Yalda Kakei, Tetiana Pylova, Amin Al-Awar, Maryna Krasnikova, Ermir Zulfaj, Abhishek Jha, Axel Andersson, Valentyna Sevastianova, Amirali Nejat, Björn Redfors
Journal: Circulation Research (2023)

Background: Myocardial stunning is a temporary loss of contractility without irreversible histological damage. In myocardial infarction(MI), stunning could lead to acute ischemic heart failure (AIHF). We aim to establish a model of myocardial stunning in rats. Methods: Rats were randomized to either two 5 min cycles of preconditioning(PC) or non-preconditioning (NPC) before ligating LAD for 13.5 min. Echocardiography (ECHO) derived wall motion score index (WMSI). Speckle tracking assesed heart function. TTC staining determined infarction size Results: PC-13.5 yielded akinesia at 4h and recovery at 48h by WMSI. Speckle tracking showed a worsening in LVEF, global longitudinal strain (GLS), and time to peak radial strain (TP) in the ischemic segment at 4h which normalized at 48h. In NPC-13.5 at 48h, LVEF, GLS, and TP radial strain didn′t recover. TTC staining showed minimal necrosis in PC and substantial necrosis in NPC. Conclusion: The study characterized a reproducible model of myocardial stunning. ECHO showed a human-like course of myocardial stunning. TTC showed absence of irreversible damage.
Abstract P3208: Trem2 Promotes Cardiac Repair In Myocardial Infarction Via Slc25a53 And Carbohydrate Metabolism After Improving Efferocytosis Of Macrophage
Authors: shiyu gong, ming zhai, jiayun shi, guanye yu, zhijun lei, Wenhui Peng
Journal: Circulation Research (2023)

Background: Efferocytosis and metabolic reprogramming of macrophages are necessary for myocardial infarction (MI) reparation. TREM2 is a transmembrane immune receptor that improves macrophage efferocytosis. we aim to uncover the effect of TREM2 + macrophage and explore the link between efferocytosis and metabolism in MI. Methods: Transgenic mice were used to determine the function of TREM2 in MI. Efferocytosis and metabolic functions were examined using flow cytometry, immunofluorescence. Targeted Metabolomics (LC-MS) was used to detect concentrations of metabolites. RNA-seq was used to screen the potential downstream pathways of TREM2. Protein and molecular docking were predicted with AutoDock Vina software. Result: Macrophage-specific TREM2 knockout mice (Mac-TREM2KO) showed worsened cardiac function and impaired post-MI repair. Deletion of TREM2 induced macrophages to transform into a pro-inflammatory phenotype of CCR2 + MHCII high . On the contrary, macrophages expressing TREM2 had decreased SLC25A53 transcription through the SYK-SMAD4 signaling pathway, which impaired NAD + transport into mitochondria, thereby restricting the tricarboxylic acid cycle and increasing itaconate production in anoxia condition. In vitro, itaconate secreted by TREM2 + macrophage inhibited cardiomyocyte apoptosis and increased fibroblast proliferation. Conclusion: Our data described a novel role of myeloid-derived macrophages-specific TREM2 in MI, linking efferocytosis to metabolism during cardiac repair, mainly through mitochondria SLC25A53 transporter.
Abstract P1172: Shear-mediated Remodeling Of Platelet Surface Glycosylation: How Can Platelets Trim Their Sugar Coats?
Authors: Yana Roka-Moiia, Sabrina Lewis, Joseph E Italiano, Marvin J Slepian
Journal: Circulation Research (2023)

Mechanical circulatory support (MCS) is associated with bleeding complications often requiring multiple transfusions or reoperation. Hypershear stress within device-supported circulation promotes platelet dysfunction associated with pro-apoptosis, impaired aggregation, and microvesiculation - all contributors to bleeding. Recent studies showed that glycosylation of surface receptors, i.e. “ sugar coat ,” plays a major role in the regulation of platelet function and lifespan. We tested the hypothesis that shear stress promotes platelet surface deglycosylation by increasing platelet glycosidase activity. Methods: Human platelets were obtained from ACD-anticoagulated blood via gel filtration on Sepharose 2B. Platelets were exposed to neuraminidase and continuous shear stress in a hemodynamic shearing device. Platelets were stained with fluorophore-conjugated lectins binding terminal sialic acids (SNA I, MAL II) and galactose (ECA), anti-CD41 and anti-CD42a a/b. Multi-colored flow cytometry was used to quantify platelet surface glycosylation. Neuraminidase and galactosidase activities of intact and lysed platelets were measured using enzyme-specific fluorogenic substrates. Results: Exposure to shear stress and neuraminidase induced a significant decrease in platelet 2,6-sialylation and galactosylation, while 2,3-sialylation remained unaltered. Neuraminidase reinforced shear-mediated platelet desialylation, causing a prominent decrease in SNA binding even at low shear, and increased platelet galactose levels by unmasking the galactose residues capped by sialic acids. Shear stress resulted in a 9.5-fold increase in platelet neuraminidase and a 1.4-fold increase in galactosidase activities vs their basal levels. Neutral neuraminidase and galactosidase were upregulated by shear, while acidic isoforms did not increase, suggesting that other than lysosomal glycosidase pools are involved. Shear stress promotes platelet deglycosylation via upregulation of platelet neuraminidase and galactosidase activities. Developing therapeutic strategies for the preservation of platelet glycosylation offers significant translational potential for the pharmacologic management of MCS platelet dysfunction and bleeding.